Multi-speed transmission

ABSTRACT

A transmission of the present invention has an input member, an output member, four planetary gear sets, a plurality of coupling members and a plurality of torque transmitting devices. Each of the planetary gear sets includes first, second and third members. The torque transmitting devices may include clutches and brakes. The torque transmitting devices are selectively engageable in combinations of at least three to establish at least ten forward speed ratios and at least one reverse speed ratio.

FIELD

The invention relates generally to a multiple speed transmission havinga plurality of planetary gear sets and a plurality of torquetransmitting devices, and more particularly to a transmission having tenor more speeds, four planetary gear sets and a plurality of torquetransmitting devices.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may or may not constitute priorart.

A typical multiple speed transmission uses a combination of frictionclutches or brakes, planetary gear arrangements and fixedinterconnections to achieve a plurality of gear ratios. The number andphysical arrangement of the planetary gear sets, generally, are dictatedby packaging, cost and desired speed ratios.

While current transmissions achieve their intended purpose, the need fornew and improved transmission configurations which exhibit improvedperformance, especially from the standpoints of efficiency,responsiveness and smoothness and improved packaging, primarily reducedsize and weight, is essentially constant. Accordingly, there is a needfor an improved, cost-effective, compact multiple speed transmission.

SUMMARY

A transmission is provided having an input member, an output member,four planetary gear sets, a plurality of coupling members and aplurality of torque transmitting devices. Each of the planetary gearsets includes first, second and third members. The torque transmittingdevices are for example clutches and brakes.

In an aspect of the present invention a transmission is provided havingan input member, an output member, a first, second, third and fourthplanetary gear sets each having sun gears, carrier members and ringgears. The input member is continuously interconnected with the sun gearmember of the third planetary gear set. The output member iscontinuously interconnected with the carrier member of the fourthplanetary gear set.

Additionally, a first interconnecting member continuously interconnectsthe sun gear member of the first planetary gear set with a stationarymember, a second interconnecting member continuously interconnects thecarrier member of the first planetary gear set with the carrier memberof the second planetary gear set, a third interconnecting membercontinuously interconnects the ring gear member of the second planetarygear set with the carrier member of the third planetary gear set and afourth interconnecting member continuously interconnects the carriermember of the third planetary gear set with the ring gear member of thefourth planetary gear set.

Further, a first torque transmitting device is selectively engageable tointerconnect the sun gear member of the second planetary gear set withthe sun gear member of the third planetary gear set and the inputmember, a second torque transmitting device is selectively engageable tointerconnect the ring gear member of the first planetary gear set withthe ring gear member of the third planetary gear set, a third torquetransmitting device is selectively engageable to interconnect the ringgear member of the third planetary gear set with the carrier member ofthe fourth planetary gear set and the output member, a fourth torquetransmitting device is selectively engageable to interconnect the ringgear member of the first planetary gear set with the sun gear member ofthe fourth planetary gear set, a fifth torque transmitting device isselectively engageable to interconnect the sun gear member of the firstplanetary gear set and the stationary member with the sun gear member ofthe second planetary gear set and a sixth torque transmitting device isselectively engageable to interconnect the sun gear member of the fourthplanetary gear set with the stationary member. The torque transmittingdevices are selectively engageable in combinations of at least three toestablish at least ten forward speed ratios and at least one reversespeed ratio between the input member and the output member.

It is thus an object of the present invention to provide a transmissionhaving four planetary gear sets.

It is a further object of the present invention to provide atransmission having ten forward speeds and at least one reverse.

It is a still further object of the present invention to provide atransmission having four planetary gear sets, a plurality of couplingmembers and a plurality of torque transmitting devices.

Further objects, aspects and advantages of the present invention willbecome apparent by reference to the following description and appendeddrawings wherein like reference numbers refer to the same component,element or feature.

DRAWINGS

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

FIG. 1 is a lever diagram of an embodiment of a ten speed transmissionaccording to the present invention;

FIG. 2 is a diagrammatic view of an embodiment of a ten speedtransmission according to the present invention; and

FIG. 3 is a truth table presenting the state of engagement of thevarious torque transmitting elements in each of the available forwardand reverse speeds or gear ratios of the transmission illustrated inFIGS. 1 and 2.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses.

At the outset, it should be appreciated that in the particular exampleprovided, the ten speed automatic transmission of the present inventionhas an arrangement of permanent mechanical connections between theelements of the four planetary gear sets. A first component or elementof a first planetary gear set is permanently coupled to a stationarymember. A second component or element of the first planetary gear set ispermanently coupled to a second component or element of a secondplanetary gear set. A third component or element of the second planetarygear set is permanently coupled to second component or element of thethird planetary gear set. Finally, the second component or element ofthe third planetary gear set is permanently coupled to a first componentor element of a fourth planetary gear set.

Referring now to FIG. 1, an embodiment of a ten speed transmission 10 isillustrated in a lever diagram format. A lever diagram is a schematicrepresentation of the components of a mechanical device such as anautomatic transmission. Each individual lever represents a planetarygear set wherein the three basic mechanical components of the planetarygear set are each represented by a node. Therefore, a single levercontains three nodes: one for the sun gear, one for the planet gearcarrier, and one for the ring gear. The relative length between thenodes of each lever can be used to represent the ring-to-sun ratio ofeach respective gear set. These lever ratios, in turn, are used to varythe gear ratios of the transmission in order to achieve appropriateratios and ratio progression. Mechanical couplings or interconnectionsbetween the nodes of the various planetary gear sets are illustrated bythin, horizontal lines and torque transmitting devices such as clutchesand brakes are presented as interleaved fingers. If the device is abrake, one set of the fingers is grounded. Further explanation of theformat, purpose and use of lever diagrams can be found in SAE Paper810102, “The Lever Analogy: A New Tool in Transmission Analysis” byBenford and Leising which is hereby fully incorporated by reference.

The transmission 10 includes an input shaft or member 12, a firstplanetary gear set 14 having three nodes: a first node 14A, a secondnode 14B and a third node 14C, a second planetary gear set 16 havingthree nodes: a first node 16A, a second node 16B and a third node 16C, athird planetary gear set 18 having three nodes: a first node 18A, asecond node 18B and a third node 18C, a fourth planetary gear set 20having three nodes: a first node 20A, a second node 20B and a third node20C and an output shaft or member 22.

The input member 12 is coupled to the first node 18A of the thirdplanetary gear set 18. The first node 14A of the first planetary gearset 14 is coupled to a stationary member or the transmission housing 50.The second node 14B of the first planetary gear set 14 is coupled to thesecond node 16B of the second planetary gear set 16. The third node 16Cof the second planetary gear set 16 is coupled to the second node 18B ofthe third planetary gear set 18. The second node 18B of the thirdplanetary gear set 18 is coupled to the first node 20A of the fourthplanetary gear set 20. The output member 22 is coupled to the secondnode 20B of the fourth planetary gear set 20.

A first clutch 26 selectively connects the first node 16A of the secondplanetary gear set 16 with the first node 18A of the third planetarygear set 18 and input shaft or member 12. A second clutch 28 selectivelyconnects the third node 14C of the first planetary gear set 14 with thethird node 18C of the third planetary gear set 18. A third clutch 30selectively connects the third node 18C of the third planetary gear set18 with the second node 20B of the fourth planetary gear set 20 andoutput shaft or member 22. A fourth clutch 32 selectively connects thethird node 14C of the first planetary gear set 14 with the third node20C of the fourth planetary gear set 20. A first brake 34 selectivelyconnects the first node 16A of the second planetary gear set 16 with thestationary element or a transmission housing 50. A second brake 36selectively connects the third node 20C of the fourth planetary gear set20 with the stationary element or the transmission housing 50.

Referring now to FIG. 2, a stick diagram presents a schematic layout ofthe embodiment of the ten speed transmission 10 according to the presentinvention. In FIG. 2, the numbering from the lever diagram of FIG. 1 iscarried over. The clutches, brakes, and couplings are correspondinglypresented whereas the nodes of the planetary gear sets now appear ascomponents of planetary gear sets such as sun gears, ring gears, planetgears and planet gear carriers.

For example, the planetary gear set 14 includes a sun gear member 14A, aring gear member 14C and a planet gear carrier member 14B that rotatablysupports a set of planet gears 14D (only one of which is shown). Theplanet gears 14D are each configured to intermesh with both the sun gearmember 14A and the ring gear member 14C. The sun gear member 14A isconnected to a first shaft or interconnecting member 42 that isconnected to a stationary member 50, thus preventing rotation of sungear member 14A relative to stationary member 50 and to a second shaftor interconnecting member 44. The ring gear member 14A is connected forcommon rotation with a third shaft or interconnecting member 46. Theplanet carrier member 14B is connected for common rotation with a fourthshaft or interconnecting member 48.

The planetary gear set 16 includes a sun gear member 16A, a ring gearmember 16C and a planet gear carrier member 16B that rotatably supportsa set of planet gears 16D (only one of which is shown). The planet gears16D are each configured to intermesh with both the sun gear member 16Aand the ring gear member 16C. The sun gear member 16A is connected forcommon rotation with a fifth shaft or interconnecting member 52 and witha sixth shaft or interconnecting member 54. The ring gear member 16C isconnected for common rotation with a seventh shaft or interconnectingmember 56. The planet carrier member 16B is connected to the fourthshaft or interconnecting member 48.

The planetary gear set 18 includes a sun gear member 18A, a ring gearmember 18C and a planet gear carrier member 18B that rotatably supportsa set of planet gears 18D (only one of which is shown). The set ofplanet gears 18D are each configured to intermesh with both the sun gearmember 18A and the ring gear member 18C. The sun gear member 18A isconnected for common rotation with the input member shaft or member 12.The ring gear member 18C is connected for common rotation with an eighthshaft or interconnecting member 58. The planet carrier member 18B isconnected for common rotation with a ninth shaft or interconnectingmember 60 and with the seventh shaft or interconnecting member 56.

The planetary gear set 20 includes a sun gear member 20C, a ring gearmember 20A and a planet gear carrier member 20B that rotatably supportsa set of planet gears 20D (only one of which is shown). The set ofplanet gears 20D are each configured to intermesh with both the sun gearmember 20C and ring gear member 20A. The sun gear member 20C isconnected for common rotation with a tenth shaft or interconnectingmember 62. The ring gear member 20A is connected for common rotationwith the ninth shaft or interconnecting member 60. The planet carriermember 20B is connected for common rotation with the output shaft ormember 22 and with an eleventh shaft or interconnecting member 64.

The input shaft or member 12 is continuously connected to an engine (notshown) or to a turbine of a torque converter (not shown). The outputshaft or member 22 is continuously connected with the final drive unitor transfer case (not shown).

The torque-transmitting mechanisms or the clutches 26, 28, 30, 32 andthe brakes 34 and 36 allow for selective interconnection of the shaftsor interconnecting members, members of the planetary gear sets and thehousing. For example, the first clutch 26 is selectively engageable toconnect the fifth shaft or interconnecting member 52 with the inputshaft or member 12. The second clutch 28 is selectively engageable toconnect the third shaft or interconnecting member 46 with the eighthshaft or interconnecting member 58. The third clutch 30 is selectivelyengageable to connect the eighth shaft or interconnecting member 58 withthe eleventh shaft or interconnecting member 64. The fourth clutch 32 isselectively engageable to connect the third shaft or interconnectingmember 46 with the tenth shaft or interconnecting member 62. The firstbrake 34 is selectively engageable to connect the sixth shaft orinterconnecting member 54 with a stationary element or the transmissionhousing 50 in order to prevent the sixth shaft or interconnecting member54 from rotating relative to the transmission housing 50. The secondbrake 36 is selectively engageable to connect the tenth shaft orinterconnecting member 62 with a stationary element or the transmissionhousing 50 in order to prevent the tenth shaft or interconnecting member62 from rotating relative to the transmission housing 50.

Referring now to FIGS. 2 and 3, the operation of the embodiment of theten speed transmission 10 will be described. It will be appreciated thatthe transmission 10 is capable of transmitting torque from the inputshaft or member 12 to the output shaft or member 22 in at least tenforward speed or torque ratios and at least one reverse speed or torqueratio with a double overdrive. Each forward and reverse speed or torqueratio is attained by engagement of one or more of thetorque-transmitting mechanisms (i.e. first clutch 26, second clutch 28,third clutch 30, fourth clutch 32, first brake 34 and second brake 36),as will be explained below. FIG. 3 is a truth table presenting thevarious combinations of torque-transmitting elements that are activatedor engaged to achieve the various gear states. Actual numerical gearratios of the various gear states are also presented although it shouldbe appreciated that these numerical values are exemplary only and thatthey may be adjusted over significant ranges to accommodate variousapplications and operational criteria of the transmission 10. An exampleof the gear ratios that may be obtained using the embodiments of thepresent invention are also shown in FIG. 3. Of course, other gear ratiosare achievable depending on the gear diameter, gear teeth count and gearconfiguration selected.

To establish reverse gear, the first clutch 26, fourth clutch 32 and thesecond brake 36 are engaged or activated. The first clutch 26 connectsthe fifth shaft or interconnecting member 52 with the input shaft ormember 12. The fourth clutch 32 connects the third shaft orinterconnecting member 46 with the tenth shaft or interconnecting member62. The second brake 36 connects the tenth shaft or interconnectingmember 62 with a stationary element or the transmission housing 50 inorder to prevent the tenth shaft or interconnecting member 62 fromrotating relative to the transmission housing 50. Likewise, the tenforward ratios are achieved through different combinations of clutch andbrake engagement, as shown in FIG. 3.

It will be appreciated that the foregoing explanation of operation andgear states of the ten speed transmission 10 assumes, first of all, thatall the clutches and brakes not specifically referenced in a given gearstate are inactive or disengaged and, second of all, that during gearshifts, i.e., changes of gear state, between at least adjacent gearstates, a clutch or brake engaged or activated in both gear states willremain engaged or activated.

The description of the invention is merely exemplary in nature andvariations that do not depart from the gist of the invention areintended to be within the scope of the invention. Such variations arenot to be regarded as a departure from the spirit and scope of theinvention.

1. A transmission comprising: an input member; an output member; first,second, third and fourth planetary gear sets each having first, secondand third members; a first interconnecting member continuouslyinterconnecting the first member of the first planetary gear set with astationary member; a second interconnecting member continuouslyinterconnecting the second member of the first planetary gear set withthe second member of the second planetary gear set; a thirdinterconnecting member continuously interconnecting the third member ofthe second planetary gear set with the second member of the thirdplanetary gear set; a fourth interconnecting member continuouslyinterconnecting the second member of the third planetary gear set withthe first member of the fourth planetary gear set; and six torquetransmitting devices selectively engageable to interconnect one of thefirst, second, and third members with at least one other of the firstmembers, second members, third members, and a stationary member, andwherein the torque transmitting devices are selectively engageable incombinations of at least three to establish at least ten forward speedratios and at least one reverse speed ratio between the input member andthe output member.
 2. The transmission of claim 1 wherein a first of thesix torque transmitting devices is selectively engageable tointerconnect the first member of the second planetary gear set with thefirst member of the third planetary gear set and the input member. 3.The transmission of claim 2 wherein a second of the six torquetransmitting devices is selectively engageable to interconnect the thirdmember of the first planetary gear set with the third member of thethird planetary gear set.
 4. The transmission of claim 3 wherein a thirdof the six torque transmitting devices is selectively engageable tointerconnect the third member of the third planetary gear set with thesecond member of the fourth planetary gear set and the output member. 5.The transmission of claim 4 wherein a fourth of the six torquetransmitting devices is selectively engageable to interconnect the thirdmember of the first planetary gear set with the third member of thefourth planetary gear set.
 6. The transmission of claim 5 wherein afifth of the six torque transmitting devices is selectively engageableto interconnect the first member of the first planetary gear set and thestationary member with the first member of the second planetary gearset.
 7. The transmission of claim 6 wherein a sixth of the six torquetransmitting devices is selectively engageable to interconnect the thirdmember of the fourth planetary gear set with the stationary member. 8.The transmission of claim 1 wherein the first member of the firstplanetary gear set, the first member of the second planetary gear set,the first member of the third planetary gear set and the third member ofthe fourth planetary gear set are sun gears, the second member of thefirst planetary gear set, the second member of the second planetary gearset, the second member of the third planetary gear set and the secondmember of the fourth planetary gear set are carrier members and thethird member of the first planetary gear set, the third member of thesecond planetary gear set, the third member of the third planetary gearset and the first member of the fourth planetary gear set are ringgears.
 9. The transmission of claim 1 wherein the input member iscontinuously interconnected with the first member of the third planetarygear set and wherein the output member is continuously interconnectedwith the second member of the fourth planetary gear set.
 10. Thetransmission of claim 1 wherein two of the six torque transmittingdevices are brakes and four of the six torque transmitting devices areclutches.
 11. The transmission of claim 1 wherein the stationary memberis a transmission housing.
 12. A transmission comprising: an inputmember; an output member; first, second, third and fourth planetary gearsets each having first, second and third members, wherein the inputmember is continuously interconnected with the first member of the thirdplanetary gear set and wherein the output member is continuouslyinterconnected with the second member of the fourth planetary gear set;a first interconnecting member continuously interconnecting the firstmember of the first planetary gear set with a stationary member; asecond interconnecting member continuously interconnecting the secondmember of the first planetary gear set with the second member of thesecond planetary gear set; a third interconnecting member continuouslyinterconnecting the third member of the second planetary gear set withthe second member of the third planetary gear set; a fourthinterconnecting member continuously interconnecting the second member ofthe third planetary gear set with the first member of the fourthplanetary gear set; a first torque transmitting device selectivelyengageable to interconnect the first member of the second planetary gearset with the first member of the third planetary gear set and the inputmember; a second torque transmitting device selectively engageable tointerconnect the third member of the first planetary gear set with thethird member of the third planetary gear set; a third torquetransmitting device selectively engageable to interconnect the thirdmember of the third planetary gear set with the second member of thefourth planetary gear set and the output member; a fourth torquetransmitting device selectively engageable to interconnect the thirdmember of the first planetary gear set with the third member of thefourth planetary gear set; a fifth torque transmitting deviceselectively engageable to interconnect the first member of the firstplanetary gear set and the stationary member with the first member ofthe second planetary gear set; and a sixth torque transmitting deviceselectively engageable to interconnect the third member of the fourthplanetary gear set with the stationary member, and wherein the torquetransmitting devices are selectively engageable in combinations of atleast three to establish at least ten forward speed ratios and at leastone reverse speed ratio between the input member and the output member.13. The transmission of claim 12 wherein the first member of the firstplanetary gear set, the first member of the second planetary gear set,the first member of the third planetary gear set and the third member ofthe fourth planetary gear set are sun gears, the second member of thefirst planetary gear set, the second member of the second planetary gearset, the second member of the third planetary gear set and the secondmember of the fourth planetary gear set are carrier members and thethird member of the first planetary gear set, the third member of thesecond planetary gear set, the third member of the third planetary gearset and the first member of the fourth planetary gear set are ringgears.
 14. The transmission of claim 12 wherein the stationary member isa transmission housing.
 15. A transmission comprising: an input member;an output member; first, second, third and fourth planetary gear setseach having sun gears, carrier members and ring gears, wherein the inputmember is continuously interconnected with the sun gear member of thethird planetary gear set and wherein the output member is continuouslyinterconnected with the carrier member of the fourth planetary gear set;a first interconnecting member continuously interconnecting the sun gearmember of the first planetary gear set with a stationary member; asecond interconnecting member continuously interconnecting the carriermember of the first planetary gear set with the carrier member of thesecond planetary gear set; a third interconnecting member continuouslyinterconnecting the ring gear member of the second planetary gear setwith the carrier member of the third planetary gear set; a fourthinterconnecting member continuously interconnecting the carrier memberof the third planetary gear set with the ring gear member of the fourthplanetary gear set; a first torque transmitting device selectivelyengageable to interconnect the sun gear member of the second planetarygear set with the sun gear member of the third planetary gear set andthe input member; a second torque transmitting device selectivelyengageable to interconnect the ring gear member of the first planetarygear set with the ring gear member of the third planetary gear set; athird torque transmitting device selectively engageable to interconnectthe ring gear member of the third planetary gear set with the carriermember of the fourth planetary gear set and the output member; a fourthtorque transmitting device selectively engageable to interconnect thering gear member of the first planetary gear set with the sun gearmember of the fourth planetary gear set; a fifth torque transmittingdevice selectively engageable to interconnect the sun gear member of thefirst planetary gear set and the stationary member with the sun gearmember of the second planetary gear set; and a sixth torque transmittingdevice selectively engageable to interconnect the sun gear member of thefourth planetary gear set with the stationary member, and wherein thetorque transmitting devices are selectively engageable in combinationsof at least three to establish at least ten forward speed ratios and atleast one reverse speed ratio between the input member and the outputmember.
 16. The transmission of claim 15 wherein the stationary memberis a transmission housing.